2020 QG

2020 QG, also known by its internal designation ZTF0DxQ,^[3] is an Earth-crossing asteroid, a few meters in diameter. It belongs to the Apollo group, and passed above the surface of Earth approximately 2,950 kilometres (1,830 mi) away^[b] (less than half an Earth radius) on 16 August 2020 at 04:09 UT.^[4] It was first imaged by the Zwicky Transient Facility (ZTF) at the Palomar Observatory about 6 hours after this closest approach, and was later identified by Kunal Deshmukh, a student at the Indian Institute of Technology Bombay, along with colleagues Kritti Sharma, Chen-Yen Hsu and Bryce T. Bolin analyzing images from the ZTF.^[5][2]

At the time, 2020 QG passed closer to Earth than any known asteroid, except for those that became meteors. It passed closer than 2011 CQ1 and 2020 JJ.^[c] Given an absolute magnitude of 29.8, it is estimated to be around 3–6 metres (10–20 ft) in diameter^[3] so similar to Earth-impactors 2008 TC3, 2014 AA, 2018 LA, and 2019 MO.

Orbit and classification

2020 QG orbits the Sun at approximately 1.0–2.9 AU every 964.2 days (2.64 years) after its 2020 orbital perturbation by its close approach with Earth.^[6] Before perturbation, it orbited every 990.5 days (with a semi-major axis of 1.9 AU).^[4]

Before its perturbation, flying by Earth, the asteroid's orbit had an eccentricity of 0.49 and an inclination of 5.5° (with respect to the ecliptic).^[4] The asteroid came to perihelion (closest approach to the Sun) on 1 August, and then on 16 August 2020 the close approach to Earth reduced its orbital period. From the encounter with the larger gravity field, the orbital eccentricity became 0.48 and the inclination stands at 4.7°.^[6]

In May 2020, before any perturbation, the asteroid had an Earth-MOID (Minimum orbit intersection distance) of 0.00027 AU (40,000 km; 25,000 mi).^[4] Hours before the close approach the Earth-MOID was 0.0001 AU (15,000 km; 9,300 mi),^[2] the close-approach perturbation (change to orbit) bringing it closer.